Modern animal husbandry operations such as dairy farms often require the handling of relatively large numbers of animals in indoor facilities. For example, cows in a dairy operation are kept at least part of the day in stalls defining a stall resting surface. From a cow's perspective, the stall resting surface should be covered with bedding material that is comfortable to lie on, provide uniform support, be cool in the summer, be non-abrasive, and provide confident footing during reclining and rising maneuvers. From the perspective of the operator of the dairy, bedding material should not be detrimental to the health of the cows or the quality of the milk produced by the cows. Sand has been proven to be advantageous as a bedding material and is commonly used in modern dairy operations.
When used as a bedding material, sand often becomes mixed with manure and possibly other contaminants. When cleaning systems are used to remove manure from a diary facility, raw slurry material is formed containing rinse liquids, liquid manure, solids, sand, and possibly other contaminants. If possible, it is desirable to convert components of the raw slurry mixture to usable materials and/or reuse the components of the raw slurry mixture.
The present invention relates to the removal of particulate material such as sand from raw slurry mixtures so that the sand may be reused. Removal of sand from the raw slurry material further forms a processed slurry (low sand content) that is more appropriate for further processing operations such as extraction of water, composting, and/or digesting.